System and method for connecting and aligning a compliant guide

ABSTRACT

A technique enables subsea intervention operations in which a compliant guide is deployed for connection with a subsea installation. A tool is provided to engage a lower end of the compliant guide in a manner that enables selective movement of the lower end between desired positions. For example, the tool may comprise a displacement mechanism that can be actuated to move the lower end of the compliant guide between an engaged position with the subsea installation and a remote parked position relative to the subsea installation.

BACKGROUND

The retrieval of desired fluids, such as hydrocarbon based fluids, is pursued in subsea environments. Production and transfer of fluids from subsea wells relies on subsea installations, subsea flow lines and other equipment. Additionally, preparation and servicing of the subsea well relies on the ability to conduct subsea intervention work.

Subsea intervention work involves numerous challenges not normally faced when working on land wells or offshore platforms. In many cases, intervention in subsea wells is performed from a floating platform or ship by extending the borehole to a surface location by a tensioned riser. Also, compliant guides can be connected between the ship and a subsea installation so that various intervention tools can be moved through the compliant guide to the subsea installation and into a wellbore.

Although many types of tools can be moved through the compliant guide, certain types of tools or tool strings are more easily deployed to the subsea facility through the open water. Various procedures also are better performed without the compliant guide. As a result, the use of certain types of tools and procedures can be limited when a compliant guide is employed between the surface vessel and the subsea installation.

SUMMARY

In general, the present invention provides a technique for subsea intervention operations in which a compliant guide, such as a spoolable compliant guide, is deployed for connection with a subsea installation. The technique utilizes a tool that engages a lower end of the compliant guide to enable selective movement of the lower end between desired positions. For example, the tool may comprise a displacement mechanism that can be selectively actuated to move the lower end of the compliant guide between an engaged position with the subsea installation and a remote parked position relative to the subsea installation.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:

FIG. 1 is a schematic front elevation view of a subsea intervention system, according to an embodiment of the present invention;

FIG. 2 is a schematic representation illustrating movement of a lower end of a compliant guide between an engaged position and a remote parked position, according to an embodiment of the present invention;

FIG. 3 is a front elevation view of a tool positioning a lower end of a compliant guide with respect to a subsea installation, according to an embodiment of the present invention;

FIG. 4 is a view similar to that of FIG. 3 but showing the tool in a different operational position, according to an embodiment of the present invention;

FIG. 5 is a view similar to that of FIG. 3 but showing the tool in a different operational position, according to an embodiment of the present invention;

FIG. 6 is a view similar to that of FIG. 3 but showing the tool in a different operational position, according to an embodiment of the present invention;

FIG. 7 is a front elevation view of another example of the tool positioning a lower end of a compliant guide with respect to a subsea installation, according to an alternate embodiment of the present invention;

FIG. 8 is a view similar to that of FIG. 7 but showing the tool in a different operational position, according to an embodiment of the present invention;

FIG. 9 is a view similar to that of FIG. 7 but showing the tool in a different operational position, according to an embodiment of the present invention; and

FIG. 10 is a view similar to that of FIG. 7 but showing the tool in a different operational position, according to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

The present invention generally relates to a technique for facilitating intervention operations with respect to subsea wells. The technique involves the use of a compliant guide deployed between a surface vessel and a subsea installation. The tool is coupled to a lower end of the compliant guide to enable selective movement of the lower end to a plurality of positions. For example, the tool can be used to move the lower end between an engaged position with the subsea installation and a remote parked position relative to the subsea installation. When in the engaged position, access is provided to the subsea installation and a wellbore beneath the subsea installation through the compliant guide. However, when in the remote parked position, direct access is provided to the subsea facility through open water without requiring movement through the compliant guide. The ability to move the lower end of the compliant guide between desired positions enables a wide variety of intervention applications and procedures.

The compliant guide may comprise a spoolable compliant guide deployed to the subsea installation from a surface vessel or other surface facility. The tool can be mounted on or adjacent to the subsea installation for engagement with the lower end of the compliant guide. In some applications, all or part of the tool can be mounted to the lower end of the compliant guide and lowered to the subsea installation with the compliant guide.

By way of example, the tool may function as an alignment and connection tool able to connect the compliant guide onto an upper portion of a subsea intervention package stack that forms part of the subsea installation. In this example, the tool also is able to disengage the compliant guide from the subsea installation and to move a lower end of the compliant guide to an adjacent parked position. The tool can be used to make multiple connections and disconnections between the compliant guide and the subsea installation without having to recover subsea equipment to the surface. In one embodiment, the compliant guide is selectively connected and disconnected from a lubricator package of the subsea installation. When the tool is used to move the lower end of the compliant guide to the parked position, direct vertical access is provided to the subsea intervention package stack. The direct vertical access enables use of a lifting apparatus, such as a vessel crane, without recovering the compliant guide to the surface. In many applications, the direct access facilitates various procedures, such as loading and/or recovering certain types of downhole well intervention equipment and wellbore plugs located within a lubricator.

Referring generally to FIG. 1, an intervention system 20 is illustrated according to an embodiment of the present invention. In this embodiment, system 20 comprises a compliant guide 22, e.g a spoolable compliant guide, and a tool 24 coupled to a lower end 25 of the compliant guide 22. Compliant guide 22 is coupled between a subsea facility/installation 26 and a surface vessel 28, such as an intervention vessel located at a surface 30 of the sea. Subsea installation 26 may be located on or at a seabed floor 32.

Compliant guide 22 is flexible guide that may be arranged in a variety of curvilinear shapes extending between a surface location, e.g. intervention vessel 28, and subsea facility 26. Compliant guide 22 also may be constructed as a tubular member formed from a variety of materials that are sufficiently flexible, including metal materials of appropriate cross-section and composite materials.

Depending on the type or types of intervention operations conducted, system 20 may comprise a variety of components. For example, a dynamic seal assembly 34 may be deployed in the compliant guide 22 or, alternatively, in subsea installation 26. In some applications, the dynamic seal assembly 34 may be run down through compliant guide 22 with an intervention tool 38, e.g. tool string, deployed by a conveyance 40. Conveyance 40 may be a flexible, cable-type conveyance, such as a wireline or slickline. However conveyance 40 also may comprise stiffer mechanisms including coiled tubing and coiled rod. Either conveyance 40 or another conveyance, such as a lift line, can further be used to deploy intervention tool 38 and other equipment to subsea installation 26 through the open water when compliant guide 22 is moved to a remote parked position via tool 24.

Although a variety of subsea installations 26 can be utilized depending on the particular environment and type of intervention operation, one example is illustrated in FIG. 1. In this example, the subsea installation 26 comprises a subsea wellhead 44, which may include a Christmas tree, coupled to a subsea well 46 having a wellbore 48. The illustrated subsea installation 26 further comprises a subsea lubricator 50 and a lubricating valve 52 that may be deployed directly above subsea wellhead 44. Lubricating valve 52 can be used to close the wellbore 48 during certain intervention operations, such as tool change outs. A blowout preventer 54 may be positioned above lubricating valve 52 and may comprise one or more cut-and-seal rams 56 able to cut through the interior of the subsea installation and seal off the subsea installation during an emergency disconnect. The subsea installation 26 also may comprise a second blowout preventer 58 positioned above blowout preventer 54 and comprising one or more sealing rams 60 able to seal against the conveyance 40.

Many additional or alternate components can be incorporated into intervention system 20 depending on the specific intervention application. For example, one or more emergency disconnect devices 62 can be positioned, generally at an upper end of compliant guide 22 and/or at the lower end of the compliant guide. Also, the subsea facility components can be arranged in many configurations. For example, the lubricator 50 may comprise a lower lubricator package and an upper lubricator package.

In operation, the tool 24 is used to move the lower end 25 of compliant guide 22 to a plurality of positions relative to subsea installation 26. For example, the tool 24 can be used to move lower end 25 between a connected or engaged position 64 and a parked position 66, as illustrated schematically in FIG. 2. In some embodiments, tool 24 can be programmed or otherwise controlled to move the lower end 25 to additional predetermined positions. Also, the distance compliant guide 22 is moved relative to subsea installation 26 can be selected according to the space required when intervention tools are moved down through the open water to subsea facility 26 and according to other operational parameters. Depending on the operational requirements, an offset distance 68 and/or a tool size envelope 70 can be selected to define the movement or potential movement of lower end 25 relative to subsea installation 26. Tool 24 is constructed to perform according to these operational requirements.

One example of tool 24 is illustrated in FIG. 3. In this embodiment, the tool 24 is a self-contained remotely controlled structure that moves lower end 25 between parked and engaged positions. The structure of tool 24 is sufficient to suitably resist forces exerted by the compliant guide 22 as a result of environmental effects, including the inherent buoyancy load of the compliant guide. When moving the lower end 25 to an engaged position with the subsea facility, the tool 24 aligns and connects a suitable connector 72 of the lower end 25 with, for example, a lubricator top hub 74 of subsea installation 26. A connector clamp 76 can be used to secure lower end 25 to subsea installation 26 in a manner that contains the well pressure. A variety of connection clamps are known and available for use in making subsea connections.

In the embodiment illustrated, tool 24 is connected between lower end 25 and a mounting structure 78 of subsea installation 26. Additionally, tool 24 comprises a displacement mechanism 80 that can be selectively actuated to move the lower end 25. In this example, displacement mechanism 80 comprises an articulated arm 82 that can be selectively articulated to move lower end 25 relative to subsea installation 26. By way of example, articulated arm 82 may be a hydraulic mechanism operated via suitable hydraulic and/or other control signals sent from the surface via control lines 84. In an alternate embodiment, hydraulic power for operating the tool 24 can be supplied by a subsea hydraulic power pack, such as a hydraulic power pack of the type often installed in remotely operated vehicles.

In FIG. 3, lower end 25 of compliant guide 22 is illustrated in a parked position that allows direct vertical access to lubricator top hub 74. However, upon receipt of appropriate control signals via, for example, control lines 84, articulated arm 82 forces lateral movement of lower end 25, as illustrated in FIG. 4. The lateral movement is continued until connector 72 of lower end 25 is properly oriented over the subsea facility, e.g. over lubricator top hub 74, as illustrated in FIG. 5. Continued hydraulic input to tool 24, via articulated arm 82, causes lower end 25 to move downwardly into full engagement with the subsea installation 26. For example, connector 72 is moved into full engagement with the lubricator top hub 74, as illustrated in FIG. 6. In this embodiment, articulated arm 82 is described as a hydraulic, articulated arm that responds to hydraulic signals. However, other types of mechanisms, e.g. solenoid driven mechanisms, also can be used to move lower end 25 relative to subsea installation 26. Regardless, the articulated arm 82 can be actuated repeatedly to move lower end 25 between engaged and parked positions.

Another example of well tool 24 is illustrated in FIG. 7. In this embodiment, subsea installation 26 includes the lubricator/lubricator package 50 in which the lubricator top hub 74 is exposed for connection with the lower end 25 of compliant guide 22. As illustrated, compliant guide 22 comprises a spoolable compliant guide having a connection assembly, e.g. connector 72, positioned at lower end 25. The displacement mechanism 80 of tool 24 comprises a four bar linkage 86 that is driven by a hydraulic actuator 88, although other types of actuators can be used to move the four bar linkage 86. The four bar linkage 86 is designed to control the path traversed by lower end 25 as it moves between engaged and parked positions. It should be noted the design is not limited to four-bar mechanisms and other multi-bar mechanisms can be constructed and used to control the path traversed by lower end 25.

In the embodiment illustrated in FIG. 7, tool 24 further comprises a guide system 90 used to connect toll 24 between subsea installation 26 and lower end 25. As illustrated, guide system 90 comprises a guide member 92 mounted on subsea installation 26 and an alignment member 94, e.g. an alignment pin, coupled to lower end 25 via, for example, four bar linkage 86. Guide member 92 may be in the form of a guide funnel sized to receive alignment member 94 and having a guide track 96. Guide track 96 may be in the form of an orientation helix used to rotationally orient alignment member 94, and thus tool 24, as alignment member 94 is inserted into guide member 92. Guide member 92 and alignment member 94 enable deployment of displacement mechanism 80 with compliant guide 22 and also ensure the proper rotational orientation of the tool 24 relative to subsea installation 26.

As lower end 25 of compliant guide 22 is lowered toward subsea installation 26, alignment member 94 moves into position over guide member 92, as illustrated in FIG. 7. Continued downward movement of lower end 25 forces alignment member 94 down through guide member 92, and this motion rotationally orients tool 24 with respect to subsea installation 26 via guide track 96, as illustrated in FIG. 8. The rotational orientation also can be used to cause engagement of other components, such as hydraulic actuator 88 which is positioned for engagement with a suitable mounting mechanism 98 of subsea installation 26. Alignment member 94 can be latched with or otherwise connected to guide member 92 to secure tool 24 until the compliant guide 22 is withdrawn to the surface or otherwise lifted away from the subsea installation.

Once alignment member 94 is engaged with guide member 92, four bar linkage 86 can be actuated via hydraulic actuator 88, as illustrated in FIG. 9. The hydraulic actuator 88 and four bar linkage 86 cooperate to move lower end 25 along a desired path into position over subsea installation 26, e.g. over lubricator top hub 74. Continued actuation of the four bar linkage causes lower end 25 to move downwardly into full engagement with the subsea installation 26, as illustrated in FIG. 10. The hydraulic actuator 88 can be used repeatedly in cooperation with the four bar linkage 86 to move the lower end 25 between an engaged position, as illustrated in FIG. 10, and a parked position, such as the position illustrated in FIG. 8.

Intervention system 20 is useful in many types of environments to facilitate a wide variety of intervention operations. Tool 24 enables an operator to avoid recovery of the compliant guide in a manner that greatly improves operational efficiency by saving time and reducing wear on the equipment. Furthermore, tool 24 can be formed from a variety of mechanical components, and various types of actuators can be used to actuate the tool as desired for a given environment and/or intervention procedure. The tool 24 also can be designed to move lower end 25 relative to the subsea installation 26 along a variety of paths and over a variety of offset distances.

Although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims. 

1. A system for use in a subsea intervention operation, comprising: a subsea installation; a compliant guide; and a tool coupled between the subsea installation and the compliant guide, the tool further comprising a displacement mechanism that is actuatable to selectively move the compliant guide between an engaged position and a remote parked position relative to the subsea installation.
 2. The system as recited in claim 1, wherein the compliant guide comprises a spoolable compliant guide.
 3. The system as recited in claim 2, wherein the subsea installation comprises a lubricator package, a lower end of the spoolable compliant guide being engaged with the lubricator package when in the engaged position.
 4. The system as recited in claim 2, wherein the spoolable compliant guide extends down to the subsea installation from a surface vessel.
 5. The system as recited in claim 2, wherein the displacement mechanism comprises an articulated arm coupled between a lower end of the spoolable compliant guide and the subsea installation.
 6. The system as recited in claim 2, wherein the displacement mechanism comprises a four bar linkage coupled between a lower end of the spoolable compliant guide and the subsea installation.
 7. The system as recited in claim 2, wherein the tool further comprises a guide member mounted on the subsea installation and an alignment member coupled to the spoolable compliant guide, the guide member being positioned to engage the alignment member when the spoolable compliant guide is initially lowered to the subsea installation.
 8. The system as recited in claim 7, wherein the guide member rotationally orients the spoolable compliant guide with respect to the subsea installation.
 9. The system as recited in claim 8, wherein the guide member comprises a guide funnel and the alignment member comprises an alignment pin sized for receipt in the guide member.
 10. The system as recited in claim 6, wherein the tool further comprises a hydraulic actuator to selectively move the four bar linkage.
 11. A method for facilitating an intervention operation, comprising: coupling a tool between a lower end of a compliant guide and a subsea installation; and operating the tool to move the lower end relative to the subsea installation between an engaged position and a remote parked position.
 12. The method as recited in claim 11, further comprising delivering an intervention tool through the compliant guide and through the subsea installation to a wellbore while the tool is in the engaged position.
 13. The method as recited in claim 11, further comprising delivering an intervention tool through open water and into the subsea facility while the tool is in the remote parked position.
 14. The method as recited in claim 11, wherein coupling comprises coupling the tool, between the lower end of the spoolable compliant guide and the subsea installation.
 15. The method as recited in claim 11, wherein coupling comprises coupling the tool between the lower end of the compliant guide and a lubricator of the subsea installation.
 16. The method as recited in claim 11, wherein operating the tool comprises operating an articulated arm.
 17. The method as recited in claim 11, wherein operating the tool comprises operating a multi-bar linkage mechanism.
 18. The method as recited in claim 11, wherein operating comprises utilizing hydraulics to operate the tool.
 19. The method as recited in claim 11, further comprising utilizing a guide member to orient the tool when the tool is delivered to the subsea installation via the compliant guide.
 20. A method, comprising: mounting a tool at a subsea installation; and using the tool to move a lower end of a compliant guide to a plurality of selected positions relative to the subsea installation.
 21. The method as recited in claim 20, wherein using comprises using the tool to move the lower end of a spoolable compliant guide.
 22. The method as recited in claim 20, wherein using comprises using the tool to move the lower end between an engaged position, in which an intervention tool can be delivered into the subsea installation through the compliant guide, and a remote parked position.
 23. The method as recited in claim 20, wherein mounting comprises mounting the tool directly to the subsea installation.
 24. The method as recited in claim 23, wherein mounting comprises mounting a hydraulic actuator. 